Retainer removal means



Oct. 8, 1963 J. F. NEWCOMB 3,106,122

RETAINER REMOVAL MEANS Filed June 15, 1960 IN VEN TOR. fi'zrr Z We zuco m United States Patent 3,l%,l22 RETAINER REMOVAL MEANS John F. Newcomb, Southficld, Mich, assignor to Allied Products Corporation, Detroit, Mich, a corporation of Michigan Filed June 15, 1160, Ser. No. 36,4(33 1 Claim. (Cl. 83698) This invention broadly pertains to punch and die retainers for use in metal stamping presses and more particularly to an improved punch and die retainer incorporating means therein for facilitating the separation of the retainer from the bed and movable slide of a press or intermediate supporting structure thereof.

In presses for metal stamping, blanking, punching and the like, the punches and die buttons are customarily removably mounted in suitable punch and die retainers that are detachably secured to die shoes aifixed to the bed and movable slide of the press. The die shoes are conventionally provided with a plurality of dowel or alignment pins projecting therefrom which are adapted to slidably engage suitably sized bores in the punch and die retainer so as to appropriately position the retainers and punch and die held thereby relative to the die shoe. To insure accurate registry of the mating punch and die sections as they come together it is necessary that the clearance between the alignment pins and bores in the punch and die retainer be kept to a small magnitude, often in the order of a few ten-thousandths of an inch, so as to minimize relative movement therebetween. Because of the comparatively close fit between the alignment pins and bores, binding frequently occurs and great diflioulty is experienced in separating the retainers from the shoe as is often required for various reasons.

It has heretofore been the practice to separate the retainer from the shoe by prying, hammering, and otherwise jarring the mating parts in order to overcome the binding coaction therebetween. Such methods have not only been tedious and time consuming but frequently result in physical damage to the accurately machined parts necessitating premature replacement of the retainer or shoes, or both.

Accordingly, it is a primary object of the present invention to provide an improved retainer incorporating means therein for simply and quickly removing the retainer from the die shoe without binding and physically abusing the accurately machined aligning surfaces.

Another object of this invention is to provide an improved retainer adapted to receive extractor means disposed in abutting relationship with the projecting ends of the alignment pins for smoothly separating the retainer from the die shoe.

The foregoing and other objects of this invention are achieved by counterboring and tapping the aligning bores in the retainer for receiving extractor screws in threaded engagement therewith and adapted to abut the end portions of the aligning pins so as to evenly strip the retainer from the die shoes as the extractor screws are progressively and alternately turned inwardly.

Other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a bottom plan view of a typical circular punch or die retainer incorporating the preferred embodiments of this invention and detachably secured to the face surface of a die shoe;

FIG. 2 is a transverse vertical section view of the punch or die retainer shown in FIGURE 1 and taken along line 2-2 thereof;

FIG. 3 is a fragmentary transverse vertical section view 3,106,122 Patented Oct. 8, 1963 taken through the center of the punch or die retainer shown in FiGUR-E 1 along line 33 thereof and looking in the direction of the arrows; and

FIG. 4 is a transverse vertical section View taken substantially along the line 4-4 of FIGURE 1 and looking in the direction of the arrows, and illustrating the retainer in a partially removed position through the use of extractor screws.

Referring now to the drawings and as may be best seen in FIGURES 1-3, an improved retainer lil incorporating the preferred embodiments of this invention is disposed with the fiat base surface 12 thereof in bearing contact with a face surface 14 of a suitable die shoe 16 and detachably secured thereto. The specific retainer 10 herein disclosed is of a two-piece construction facilitating the manufacture thereof and comprising a base pad 1'8 and a block member 20' fixedly secured together. The block member 20 is provided with a suitably sized central bore 22 disposed substantially perpendicular to the base surface 12 and is adapted to receive and removably secure a cylindrical shank 24 of a suitable punch. The shank 2-4 is provided with a suitable teardrop-shaped groove 26 along the periphery thereof as may be best seen in FIG. 3 which is adapted to be engaged by a suitable resiliently biased ball retainer mechanism preventing inadvertent withdrawal of the punch from the central bore 22. The ball retainer mechanism is comprised of a hardened ball 23 and a coil spring 30 positioned in an angularly disposed bore 32 in the block member 26 and communicating at its lower end with the central bore 22 at a point adjacent to the groove 26 in the shank 24. To release the punch from the retainer 10 a suitable release pin (not shown) is inserted upwardly in an aperture 3-4 disposed adjacent to the central bore 22 whereby the hardened ball 28- is pushed in opposition to the biasing force of the coil spring 30 out of engaging contact with the groove 26 in the shank 24- enabling the withdrawal of the punch from the retainer.

The retainer it) is detachably secured to the face surface 14 of the die shoe 16 by means of a pair of socket head type cap screws 36 having the head portions thereof recessed in the block member 29 and the shank portions thereof extending upwardly through bores 38 through the block member 20 and the base pad 18 and in threaded engagement with tapped bores 49 in the die shoe l6. Accurate alignment of the retainer 10 with respect to the die shoe 16 is achieved by alignment pins 42a and 42b secured to the die shoe 16 and projecting substantially perpendicular to the face surface 14 thereof and having their lower end portions, as viewed in FIG. 2, closely fitted in aligning bores 44a and 4412, respectively, in the block member 20'. The bores 46a and 46!) through the base pad 18 disposed in axial alignment with the aligning bores 44a, 44b in the block member 20 are of a slightly greater diameter to prevent binding and provide preliminary alignment of the retainer 10 during the installation of the retainer on the die shoe 16. The aligning bores 44a, 44b are provided with counterbores 48a, 48b, respectively, and are tapped to a depth corresponding to the downward projecting point of alignment pins 42a, 42b. The tapped counterbores 48a, 48b are adapted to receive extractor screws 5%, 5%, respectively, which areprovided with socket type apertures in the head portion thereof for receiving and engaging a suitable socket type wrench 52. As shown in FIG. 4, the extractor screws 50a, 50b are provided with cylindrically shaped shank portions 54a, 54b, respectively, having a diameter less than the aligning bores 44a, 44b in the block member 20 and are of a length substantially equal to the length of the pin engaging surface of the aligning bores. The end surfaces of the shanks 54a, 54b are adapted to abut 3 l the projecting ends of the alignment pins 42a, 42b, respectively, as the extractor screws are turned inwardly in the tapped counterbores 48a, 4 31).

The retainer 14) is shown in FIG. 2 in the fully installed position. When it :becomes necessary to remove the retainer 19' from the die shoe to it is preferred to first remove the punch by disengaging the ball 28- from the groove 26 in the shank 24 thereby enabling withdrawal of the punch from the central bore 2 2. The cap screws 36 are next removed and the extractor screws 50a, 59b are turned into the tapped eounterhcres 43a, 43b until the end of the shank portions 54a, 54!) thereof contact the projecting end portions of the alignment pins 42a, 4212, respectively. The extractor screws 5%, 56b are then uniformly turned whereby the retainer 16 is stripped off the alignment pins 42a, @215 as shown in FIG. 4 in the direction of the arrow. The uniform operation of the extractor screws 5 a, 31; is necessary to maintain the alignment pins 42a, 42b in axial alignment with aligning bores 44a, 44b thereby minimizing binding therebetween during the stripping operation. This can conveniently be achieved by alternately turning the extractor screws Eda, 5612 a fraction of a turn until the end portions of the alignment pins 42a, 42b are released from aligning bores 44a, 44b in the block member 26*.

It will of course be appreciated by those skilled in the art that the means and method hereinabove described in relation to the specific retainer shown in the drawings is equally applicable to other types of retainers having one or more alignment pins closely fitted and in sliding contact with aligning bores in the die retainer. Accordingly, While the preferred embodiment herein described is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change Without departing from the proper scope or fair meaning of the subjoined claim.

What is claimed is:

In a punch and die retainer detachably mounted on a support member and aligned thereon by a plurality of pins afiixed to and projecting fromthe support member and disposed in sliding engagement in each of a plurality of aligning bores that extend inwardly from one surface partly through the retainer, the improvement comprising separating means for stripping said retainer from the alignment pins, said separating means com prising a portion defining a tapped bore extending inwardly from a surface opposite to the one surface of said retainer and in end-abutting communication and axial alignment with each of the plurality of aligning bores in said retainer, screw means removably disposed and in threaded engagement in each of said tapped bores, said screw means having a shank portion integrally afi'ixed thereto and disposed in axial abut-ting relationship with the projecting end portions of each of the pins whereby said retainer is evenly stripped from the pins as said screw means are uniformly turned inwardly in said threaded bores.

References Cited in the file of this patent UNITED STATES PATENTS 328,235 Latta Oct. 13, 1885 1,804,935 Jacobus May 12, 1931 2,245,676 Johnson June 17, 1941 2,635,338 Dallenbach Apr. 21, 1953 3,034,464 Hrabal May 15, 1962 

